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AUSCERT External Security Bulletin Redistribution
ESB-2021.1255
JSA11115 - 2021-04 Security Bulletin: Junos OS:
FreeBSD-SA-19:04.ntp : Authenticated denial of service in
ntpd
15 April 2021
===========================================================================
AusCERT Security Bulletin Summary
---------------------------------
Product: Junos OS
Publisher: Juniper Networks
Operating System: Juniper
Impact/Access: Denial of Service -- Remote/Unauthenticated
Resolution: Patch/Upgrade
CVE Names: CVE-2019-8936
Reference: ESB-2020.3427
ESB-2019.1040.2
ESB-2019.0744
Original Bulletin:
http://kb.juniper.net/InfoCenter/index?page=content&id=JSA11115
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2021-04 Security Bulletin: Junos OS: FreeBSD-SA-19:04.ntp : Authenticated denial of service in ntpd (CVE-2019-8936)
Article ID : JSA11115
Last Updated: 14 Apr 2021
Version : 4.0
Product Affected:
This issue affects Junos OS 12.3, 12.3X48, 14.1X53, 15.1, 15.1X49, 15.1X53,
16.1, 16.2, 17.1, 17.2, 17.3, 17.4, 18.1, 18.2, 18.3, 18.4, 19.1, 19.2, 19.3.
Problem:
On Juniper Networks Junos OS devices where ntp is enabled a crafted malicious
authenticated mode 6 packet from a permitted network address can trigger a NULL
pointer dereference. Note for this attack to work, the sending system must be
on an address from which the target ntpd accepts mode 6 packets, and must use a
private key that is specifically listed as being used for mode 6 authorization.
The ntpd daemon can crash due to the NULL pointer dereference, causing a Denial
of Service (DoS).
Continued receipt and processing of these crafted malicious packets will create
a sustained Denial of Service (DoS) condition.
This issue affects:
Juniper Networks Junos OS:
o 12.3 versions prior to 12.3R12-S15 on EX Series;
o 12.3X48 versions prior to 12.3X48-D95 on SRX Series;
o 14.1X53 versions prior to 14.1X53-D53, 14.1X53-D140 on EX Series;
o 15.1 versions prior to 15.1R7-S6;
o 15.1X49 versions prior to 15.1X49-D200 on SRX Series;
o 15.1X53 versions prior to 15.1X53-D593 on EX2300 Series, EX3400 Series;
o 16.1 versions prior to 16.1R7-S7;
o 16.2 versions prior to 16.2R2-S11, 16.2R3;
o 17.1 versions prior to 17.1R2-S11, 17.1R3-S2;
o 17.2 versions prior to 17.2R1-S9, 17.2R3-S3;
o 17.3 versions prior to 17.3R2-S5, 17.3R3-S7;
o 17.4 versions prior to 17.4R2-S9, 17.4R3;
o 18.1 versions prior to 18.1R3-S9;
o 18.2 versions prior to 18.2R2-S6, 18.2R3-S3;
o 18.3 versions prior to 18.3R1-S7, 18.3R2-S3, 18.3R3-S1;
o 18.4 versions prior to 18.4R1-S5, 18.4R2-S4, 18.4R3;
o 19.1 versions prior to 19.1R1-S4, 19.1R2-S1, 19.1R3;
o 19.2 versions prior to 19.2R1-S3, 19.2R2;
o 19.3 versions prior to 19.3R1-S1, 19.3R2-S1, 19.3R3.
The following minimal configuration example is provided:
[system ntp]
Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
This issue was discovered during a external security research.
This issue has been assigned CVE-2019-8936
Solution:
The following software releases have been updated to resolve this specific
issue: 12.3R12-S15, 12.3X48-D95, 14.1X53-D53, 14.1X53-D140, 15.1R7-S6,
15.1X49-D200, 15.1X53-D593, 16.1R7-S7, 16.2R2-S11, 16.2R3, 17.1R2-S11,
17.1R3-S2, 17.2R1-S9, 17.2R3-S3, 17.3R2-S5, 17.3R3-S7, 17.4R2-S9, 17.4R3,
18.1R3-S9, 18.2R2-S6, 18.2R3-S3, 18.3R1-S7, 18.3R2-S3, 18.3R3-S1, 18.4R1-S5,
18.4R2-S4, 18.4R3, 19.1R1-S4, 19.1R2-S1, 19.1R3, 19.2R1-S3, 19.2R2, 19.3R1-S1,
19.3R2-S1, 19.3R3, 19.4R1, and all subsequent releases.
This issue is being tracked as 1436892 .
Workaround:
Use ' restrict noquery ' options in the ntpd configuration to limit addresses
that can send mode 6 queries.
Implementation:
Software releases or updates are available for download at https://
support.juniper.net/support/downloads/
Modification History:
2021-04-14: Initial Publication.
CVSS Score:
7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
Severity Level:
High
Severity Assessment:
Information for how Juniper Networks uses CVSS can be found at KB 16446 "Common
Vulnerability Scoring System (CVSS) and Juniper's Security Advisories."
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